Adjacent Possible
Etymology
Coined by theoretical biologist Stuart Kauffman around 2002 and popularized by writer Steven Johnson. It captured how biological and technological novelty expands stepwise into what is newly reachable, rather than into all conceivable states at once. The phrase joins "adjacent," from Latin "adjacere," to lie near, with "possible."
noun phrase · /uh-JAY-sunt POS-uh-bul/
The set of next steps reachable from where a system currently stands — the new combinations the present state makes available.
What it names
A tool for thinking about how innovation and evolution actually advance: not by leaping anywhere, but by opening one door at a time, each achievement unlocking a fresh set of formerly impossible moves.
Example
You couldn’t have invented the app before the smartphone — cheap sensors and GPS had to enter the adjacent possible first.
Related idea
The forward-looking counterpart to path dependence: path dependence explains why history locks you onto a given track, while the adjacent possible maps which moves that track currently makes reachable.